Robert G. Keenan

The “USPHS” Method for Determining Lead in Air And in Biological Materials

Abstract The “USPHS” method for determination of lead in air and biological samples has been developed and tested over a quarter of a century. Complete details of procedure are presented with associated information on sampling, preferred method of ashing, purification of reagents, and other preparative procedures. An evaluation of the method for lead in blood shows mean recovery of 97.1% of lead. Among replicate analyses the coefficient of variation ranged from 4.0% to 9.5% for samples respectively containing from 0.291 to 0.020 mg Pb/100 gm blood.

The Mineral Content of Bituminous Coal Miners' Lungs

Abstract Lung samples from 30 bituminous coal miners have been analyzed for coal and noncoal dust. The latter has also been analyzed for quartz, other crystalline substances, and metallic constituents. Initially, the sample is freeze-dried, and ground in a mullite ball mill, and suitable aliquots are then digested by the King and Gilchrist procedure. Following the destruction of the lung matrix, the total dust is determined gravimetrically. The loss obtained on igniting the total mineral residue at 380°C represents the weight of the coal fraction. The resulting noncoal residue is then aliquoted for the determination of quartz and for the identification of other crystalline substances by x-ray diffraction. The analysis for the metallic constituents is accomplished by emission spectrography. Particle size analysis of the noncoal fraction is conducted by an electron microscopic procedure.

Characterization and Solubility of Metals Associated with Asbestos Fibers

Abstract A series of uniform samples representing blends from different sources and types of asbestos were analyzed for nickel, chromium, cobalt and manganese. The bulk samples and the less than 10-micron size fractions were analyzed separately. The metals soluble in bovine serum were determined for the less than 10-micron fractions. Free silica content was also determined. The degree of solubility of the same metal varied considerably by source and type of asbestos. Chrysotile had greater amounts of nickel and chromium whereas Amosite was higher in manganese. Crocidalite had the lowest metal content.

Exposure to Metals in the Manufacture of Asbestos Textile Products

Abstract Asbestos textile workers processing chrysotile were exposed, in the past, to significant airborne levels of nickel, chromium, and manganese. Limited studies indicate that other metals were also involved. It is likely that the phenomenon shown in asbestos textile manufacturing is also true in other asbestos mining, milling, and processing operations. Sufficient evidence is presented in this study to indicate that the role of metals in the etiology of disease associated with asbestos inhalation should not be ignored. It is no longer tenable to look only for asbestos fibers or bodies in biological tissue and by their presence assume a cause and effect relationship with the disease.

Spectrographic Determination of Beryllium in Air, Biological Materials, and Ores Using the Sustaining A.C. Arc

Abstract A spectrographic method has been developed, using a sustaining a.c. arc, for the quantitative determination of beryllium in amounts as low as 0.001 microgram. The method is based upon the excitation of beryllium volatilized from a chloride matrix which is prepared from a lithium chloride-graphite buffer, liver ash, and the ashed or fused sample. Experiments with Be7 have provided quantitative recoveries of the radioactive tracer from urine samples and from bertrandite and beryl ores. Application of the method to samples of beryllium ores provided, in six out of eight cases, less than 10% deviations from the results of the chemical analyses reported by the U. S. Bureau of Mines.

Metal and mineral concentrations in lungs of bituminous coal miners.

Abstract The concentrations of metals and minerals in lungs of bituminous coal miners are the subject of a continuing study that includes gravimetric determinations of coal and total dust, chemical determinations of free silica, and quantitative spectrographic analyses of metallic and other elemental constituents. The free silica and the elemental constituents of the residual mineral deposits were determined by phosphoric acid and quantitative emission spectrographic methods, respectively.

Source and Identification of Respirable Fibers

Abstract Fibrous bodies with an iron-containing coating have been found in the lungs of persons coming to autopsy in a number of urban hospitals, the number of fibrous bodies varying greatly with approximately 4 to 6% of the persons examined showing numerous bodies. Because these findings raise questions with regard to the possibility that asbestos is a factor in increased lung cancer, questions concerning the nature, source, and significance of these bodies are discussed in the light of research needed to find answers.

Spectrochemical Determination of Indium and Antimony in Biological Materials

Abstract A spectrographic method for the determination of microgram amounts of indium and antimony in biological material is described. Samples are wet-ashed with nitric acid. An HCl solution containing 2 mg of ash is loaded on waterproofed electrodes charged with 5 mg of spectroscopic buffer and the gallium internal standard. The solution is evaporated to dryness in the electrode crater at 105°C. Electrodes are excited in a 220-voIt d-c arc. Spectral lines used are Ga 2943.6 A, Sb 2877.9 A, and In 3039.3 A. Concentrations as low as 1 ppm indium and 50 ppm antimony in 2 mg of ash can be determined. Mean coefficient of variation for indium is 10.9%, that for antimony is 9.9%.

Determination of submicrogram quantities of mercury in urine by ion exchange separation.

Abstract An ion exchange method for the complete separation of submicrogram and larger quantities of mercury from 0.3 to 0.5 milligram amounts of copper, lead, cadmium, thallium, zinc, and nickel is described. The mercury in a digest of a biological sample is adsorbed on an anionic resin and then eluted quantitatively with a 0.002M solution of thiourea in 0.01M HCL. The eluted mercury is complexed directly with a standard dithizone reagent and read spectrophotometrically at 490 millimicrons. The sensitivity is 0.3 microgram. Experiments with the stable isotope of mercury and with Hg-203 in urine have given recoveries exceeding 92 per cent.

Techniques for the Detection, Identification and Analysis of Fibers

Applicability and limitations of the techniques used for the detection, identification, and analysis of mineral fibers are discussed with particular emphasis as to the problem of evaluating health hazards resulting from exposure to fibers and the discovery of the mechanisms of the diseases involved.